Automatic telephone system



G. A. YANOCHOWSKI.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FlLED OCT. 2, 1916.

m 9 w v 5 9 Aw u w x m M Q E i F m H/EV r Lam T 7' P H m W EUFQE 4 G. A;YANOCHOWSKI.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED OCT. 2, 1916.

1,376,371; Patented Apr. 26, 1921.

4 SHEETS-SHEET 2.

G. A. YANOCHOWSKI.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED OCT. 2, 1916.

m rT P F. A 0 a4 F m m E M iii 590F475 174/527 Urban/5A z' 22755555Wag/9% NW G. A. YANOCHOWSKI.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED OCT. 2. 1916.

1,376,371 Patented Apr. 26, 1921.

4 SHEETS-SHEET 4.

n OR m 2 22272755555: JUL/52222721 UNITED STATES PATENT OFFICE.

GEORGE A. YANOGHOWSKI, or cnrono'o, ILLINOIS; ASSIGNOR 'ro xELLooGswrrcn- BOARD AND sunny compan or cnxcaoo, rumors, A CORPORATION orILLI- NOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Apr. 26, 1921.

Application filed October 2,1918. Serial No. 123,267.

To all whom it may concern:

Be it known that I, GEORGE A. YANO- CHOWSKI, a citizen of the UnitedStates of America, residing in Chicago, county of Cook, andState ofIllinois, have invented certain new and useful Improvements in AutomaticTelephone Systems, of which the following is a specification.

My invention relates to telephone exchange systems and more particularlyto automatic telephone systems of the two-wire or metallic line type ofthat kind in which the subscribers lines are provided with primary orindividual line switches which have access to trunks that terminate insecondary line switches which in turn have access. to trunks thatterminate in first selector switches, thereby causing at least twononnumerical trunking operations before the call reaches the firstselector switch or other 4 apparatus.

The object of my invention is the provision of a system of the abovetype which is provided with rotary primary and second ary line switches,that is, primary and secondary line switches which are each providedwith their own individual operating mechanism.

One of the features of my invention is the use of rotary primary andsecondary line switches of the type in which the wipers of the switchesdo not return to normal when a connection is released but remain uponthe terminals used in extending the connection from a subscribers lineto a first selector. Another feature of my invention is the provision ofmeans in the primary and secondary line switches to permit their wipersto remain stationary in connection with the last bank terminals usedwhen a subscriber initiates a call, providing that the trunks extendingfrom the contacts engaged by the primary and secondary line switchwipers are idle ones, thus providing a system in which a callingsubscriber may extend a call through to an-idle first selectorwithoutmoving either. the primary or secondary line switches but allowing themtoremain in their antecedent position. The. provision of switches ofthis type greatly decreases the average time taken for connecting asubscribers line 'to an idle first selector switch.

Still another feature of my invention is the provision of means forrendering all of the trunks extending from primary line switch groups toa secondary line switch group busy as soon as the first selectorsassoclated with the secondary line switch grou become busy. The featuresas above described and others will be more fullv described in theensuing specification.

Fora more complete understanding of my inventlon reference is to be madeto the accompany ng drawings which illustrate diagrammatlcally theapparatus used in estabhshmg a connection from a calling to a calledline, and in which- Flgure 1 shows a calling line and its primary lineswitch B; and a secondary line swltch to which it has access.

Fig. 2 which is placed to the right of F1g. 1, shows a first selectorswitch.

F1g. 3, which 1s placed to the right of Fig. 2, shows a connectorswitch, a called l ne and part of its primary line switch c1rcu1t.

Fig. 4 illustrates diagrammatically one method of extending the trunksfrom the prlmary line selectors to the secondary line selectors.

Referring to Fig. 1, I show a substation A which is of a Well known formof apparatus, and comprises a calling device CD in addition to theusualsubstation apparatus. The hne conductors 1 and 2 connect thesubstation A with the primary line switch B.

The line switch B is preferably a ten point rotary switch comprising tensets of contacts 7, 8, 9 and 10, circularly disposed in a well knownmanner and having cooperating Wipers 3, 4, 5 and 6, respectively, eachand 6 are moved from one contact set to the next. In the selectingoperation of the switch B, the wipers are advanced to an idle set ofcontacts and after conversation is completed they remain in connectionwith the said contacts until another selecting operation of the switch.The wiper 3 may be called an auxiliary'wiper and each contact 7 leads toa normally open contact 23 of a relay 22, the said relay 22 controllingcera apted to be energized when switch B connects with an idle secondaryline selector to extend the circuit of the calling line to said selectedsecondary line selector. A second cut-ofi' relay 00 is also provided forthe switch B, the said relay being adapted to be operated only uponconnect1on to the line of substation A as'a called line; The operationof this relay c0 removes thesubstation control of its line switch B. Arelatively slow-acting relay R is also provided for the line switch B,the said relay being adapted to be energized upon energization of itsassociated line relay LR to control certain operations, as will be moreparticularly pointed out in the ensuing specification. Each line A ismultiply connected to contacts their. operat on will be more in theensulng specification.

201 202 203 of ten connector switches which have access thereto. 4

The secondary line switch D is similar in construction to that of theprimary line switch B, and in addition a train of relays 19, 19 19 isprovided. The said chain of relays is associated with a group ofsecondary switches and is adapted to busy the incoming trunks from theprimar groups to the. secondary groups when al of the trunksleading fromthe group of secondary line switches to the first selector switches arebusy. The train of relays 19, 19 19 brings about the energization ofrelay 22 to place a ground on conductors 23 to brin about the aboveresult, and fully described The first selector D illustrated in Fig. 2comprises a set of wipers 24, 25 and 26, and cooperating sets ofcontacts 27, 28 and 29, divided into ten groups of ten contacts each.The ten groups of contacts are arranged in ten rows, each row containingten sets of contacts. The wipers are'so arranged that in the operationof the switch they are primarily adjusted in one direction to select arow of contacts, and then secondarily adjusted to select a contact inthe selected row. For adjusting the wipers in a rimary direction theprimary magnet M and associated ratchet pawl mechanism are provided,while for adjusting the wipers in a secondary direction a secondarmagnet SM and associated ratchet mec ianism are provided. Primary offnormal springs PON .are adapted to be moved to their alternate positionupon the first primary step mary relay PR is connected in bridge of theprimary and secondary conductors 1 and S, the said relay being energizedupon connection made with its associated first selector switch bycurrent flowing over the calling line. The'relay PR being connected Q inbridge of the 'lineas stated is responsive to any interruption. of itscircuit as by means of the calling device CD. A slowacting secondaryrelay SR is provided which controls the starti of the secondary movementof the switc A slow-acting main release relay MR is also provided .andis adapted to control the release of the switch. A test relay TRisadapted to be energized after the primary movement of the switch andcontrols the secondary movement of the switch in selecting an idle setof contacts. In the release of the first selector D, secondary magnet SMis again actuated to advance wipers 24, 25 and 26 beyond the lastcontact in-the selected group, whereby a release awl is actuated to.allow the wipers to erestored by a spring, the restoring movement ofthe wipers taking a different path from .the actuating movement. Inrestoring they return from their primary adjustment first and thereafterfrom their secondary adjustment. From this it will be seen that in acomplete opera tion of the switch, that is, in a selecting and releasingoperation, the wipers are first moved in a horizontal plane, but in arotary direction, to a certain row or group of contacts, and thereaftermoved in a vertical plane, but also in a rotary direction, to select acontact in the selected group. Then when released, this secondaryvertical movement is continued until the wiper passes the last contactin the selected row whereby a release pawl is operated to allow thewiper to restore by a spring first backward in a rotary horizontaldirection and thereafter downward in a rotary vertical direction, tonormal.

The connector switch E as illustrated in Fig. 3 comprises a switchstructure similar to the switch structure of first selector D. Therelays, operating magnets and oif-normal contacts of the connectorswitch E which are similar to the corresponding parts of the firstselector D have similar reference characters but with the suffix primeadded. The connector switch E also includes a line test relay LT whichis adapted, following the connection of the wipers to the terminals ofthe called line. to cause ringing current to be applied through themedium of an interrupter relay RI to the terminals of the called line ifidle, while if the called line is busy a charcuits, but I preferablyemploy such a switch as is disclosed in patent to William Kaisling forautomatlc switch for telephone systems, No. 1,131,140.

The called substation F is equipped similar to substation A and isconnected by means of line conductors '1 and 2 to the primary lineswitch 13 at the central ofiice.

Having described in general the apparatus,

scribed, and we will assume that the number of the called substation Fis 243.

To initiate a call the subscriber at the substation A removes hisreceiver from its switch hook whereby a circuit for line relay LR isestablished, the circuit being traced from battery through the windin ofline relay LR, the normal contact 30 0 relay R, normal contact 31 ofrelay )0,- the normal contact 32 of relay CO, the line conductor 2,through the substation A, back over line conductor 1, normal contact 33to ground at normal contact 34. The closing of alternate contact 35-ofrelay LR closes an energizing circuit for the relay R from batterythrough the winding of the relay R to ground at alternate contact 35. Asthe primary line switch is of the rotary non-restor ing type, one of itswipers is always engaging a contact leading to a secondary line switch,and'should the contact 8 that is engaged lead to a busy secondary lineswitch a locking circuit is established for the relay LR, when itenergizes, from battery through the winding of the said relay LR, itsalternate contact 36, conductor 37 to the grounded contact 8. Thecircuit for motor magnet M is thus established from the ungrounded poleof the generator G through the winding of the magnet M, and thealternate contact 20 of relay R to ground at alternate contact 38 ofrelay LR. The motor magnet is thus energized to step the wipers 3, 4, 5and 6 into connection with the next set of contacts. If this next set ofcontacts is busy. the wipers are stepped until an idle secondary lineswitch is encountered, and as soon as this takes place the lockingcircuit of relay LR is interrupted due to the wiper 4 A switching relay.SW is ar- 1 relay engaging an idle contact 8 leading to an idlesecondary line switch. The relay LR in restoring opens the circuit ofrelay R, but relay R being slow to release remains operated until asubstitute circuit is established for it as will now be described.

The opening of alternate contact 38 of rela LR opens the circuit ofmotor. magnet M t us preventing further operation of the wipers. U onthe deenergization of relay LR relay 0 is energized over a circuittraced from batterythrough the alternate contact 40 of rela R, throughthe winding ofthe said relay 0 to round at the normal contact 35 ofrelay L The closin alternate contacts 32 and 33 of relay C tends thecalling line to the selected second-.,

ary line switch. As soon as the relay C0 of the primary line switch B isenergized a circuit for l1ne relay LR of the selected secondary lineswitch C is established from battery through the winding of the saidrelay LR normal contact 41 of relay R normal contact 42 of relay COcontact 10, wiper 6, alternate contact 32, the line conductor 2 throughthe substation A, back over the line conductor 1, alternate contact 33,wiper 5, contact 9 to ground at normal contact 43 of relay CO. Theclosing of alternate contact 44 of relay LR establishes a circuit forthe relay R traced from battery through. the winding of the saidrelay Rto ground at alternate contact 44 of relay LR The closing of alternatecontact 45 of rela of primary line switch B, the said circuit beingtraced from battery through the winding of the "said relay R, alternatecontact 46 of relay CO, conductor 47, the wiper 4, and bank contact 8 toound at alternate contact 45 of relay R he energization of the relay Ropens the initial energizing circuit of relay LR at contact 41 butshould the test wiper 16 of the secondary line switch C be engaging abusy contact 13 a locking circuit is established for the relay LR tracedfrom battery through the winding of the said relay LR alternate contact48 of relay LR to the busy grounded contact 13 which leads to a busyfirst selector D. The relay LR and relay R are thus energizedestablishing an energizing circuit for the motor magnet M traced frombattery through the alternate contact 49 of relay LR, alternate contact50 of relay R and through the interrupter I to ground. The wipers 16, 17and 18 are thus stepped from one contact to the next, by the motormagnet M until an idle first selector has been encountered. When thistakes place the locking circuit for the relay LR is interrupted at theidle contact 13 which has been engaged by the test wiper 16 and therestoration of the said line relay LR opens the circuit of the motormagnet M R closes the substitute circuit forcontact 52 of relay LR.

thus preventing further stepping of the W1 ers.

he restoration of the line relay LR closes a circuit for the cut-offrelay CO traced from batter through the alternate contact 51 of rela Rand through the winding of the cut-0 relay CO to round at normal Ihecircuit of relay R is interrupted upon the restoration of relay LR butit being slow to release remains energized until a substitute circuit isestablished for it as will now be described. V

Although the opening of alternate contact 44 of relay LR? interrupts theenergizing circuit for said relay R the relay R being slow to releasedoes not immediately restore due to its slow to release action, andtherefore upon the energization of relay CO the calling subscribers lineis extended to the idle first selector bringing about the operation ofthe rimary relay PR, the circuit of said relay R being traced fromground throu h the left hand winding of the said relay R, the primaryconductor P, contact 14, wiper" 17, alternate -contact 43, contact 9 andwiper 5, alternate contact 33, the line conductor 1, through thesubstation back over the line conductor 2, alternate contact 32, wiper6, contact 10, alternate contact 42, wiper 18, contact 15, secondaryconductor S and tllIOligh the right hand winding of the relay P tobattery. Relay PR upon energizing, causes the closing of its alternatecontact 53 whereby a locking circuit for relay R is established, tracedfrom battery2 through the winding of the said relay alternate contact 54of relay CO wiper 16, contact 13, and through the alternate contact 53of relay PR to ground, thus maintaining the said relay R energized. Thisground connection at alternate contact 53 also places a busy or groundpotential upon the multiple contacts 13, thereby preventing any othersecondary line switch from connecting with the selected first selectorD. Also responsive to the energization of rela PR, a circuit for themain release rela hlR is established from battery through t e winding ofthe said relay MR, and through alternate contact 55 of relay PR toground at normal contact 56 of the primary off-normal switch PON, relaMB is thereupon energized and establis es a substitute circuit foritself through its alternate contact 57, this circuit being provided totake the place of its initial energizing circuit which is interruptedupon the first movement of the primaryotf-nop mal switch PON. It willthus be seen that the substation now is connected to a first selector Dand that relay PR is energized over a metallic circuit including theline conductors and the calling substation A.

The closing of alternate contact 53 of retends from ground at contact 53of relay PR at the first selector through the winding of said relay 19to battery. The last rclay of the train of relays has ground connectedto its contact and upon the energization of all the relays of the seriesa circuit is closed for relay 22 over a circuit extending from batterythrough the. relay 22 and through the alternate contacts of the chain ofrelays to ground. There is such a relay 19 associated with each firstselector of the group of first selectors associated with a group ofsecondary line switches. Should all of the first selectors of the groupof secondary switches become busy the said ground is connected throughthe alternate contacts of relays 19, etc., to the relay 22 and tobattery. The relay 22, upon energizing, closes its alternate contacts23, placing ground upon all of the trunks leading from the groups ofprimary line switches to this group of secondary line selectors.

Assuming now that a subscriber associated with one of the primary groupshaving access to this secondary group initiates a call and should thesubscribers primary switch be standing in connection with a trunkleading to this particular secondary group, it will find the bankcontact 7 grounded and the relay LR of the said primary switch willcause the primary switch to step to the next contact. The said circuitfor relay LR extends from ground at relay 22, through contact 7,rwiper3, conductor 201, alternate contact 36 alternate contact 36, and throughthe winding of the relay LR to battery, thus bringing about the steppingof theprimary line switch wipers to the next set of contacts which leadto another group of secondary line switches. If the next contact 7 nowengaged by the wiper 3 be idle, and should the contact 8 engaged by thetest wiper 4 be idle, the relay LR w1ll be deenergized thus extendingthe calling line to an idle secondary line selector. But if the testwiper 4 engages a busy contact 8, or should the wiper 3 engage a busycontact 7, the wipers 3, 4, 5 and 6 are stepped to the next set ofcontacts. From the foregoing it is apparent that a ground from eitherbank contacts 7 or a ground from a bank contact 8 brings about themovement of the wipers of the primary. line switch from one contact setto the next until an idle trunk leading to an idle secondary line switchin an idle group is encountered. When this takes place the relay LR-deenergizes as before stated and extends the calling line to the idlesecondary line switch.

N ow assuming that upon the initiation of a call by the callingsubscriber A that both the primary line switch B and secondary lineswitch C wipers are resting on idle contacts leadin to an idle secondaryline switch and an iille first selector, respectively, the operation ofthe primary and secondary switches is as follows: The subscriber uponthe removal of the receiver at the calling substation A brings about theenergization of the line relay LR of the primary line switch B, aspreviously described, and the said relay, upon energizing closes acircuit for the relay R. Relay R, upon energizing opens the circuit forrelay LR and as wipers 34 are in engagement with idle contacts relay LRimmediately deenergizes. The contacts 20 and 30 relay R are so adjustedthat the normal contact 30 breaks before contact 20 makes, and as therelay LR is a quick-acting relay it immediately restores and opens itscontact 38 before contact 20 of relay R completes the circuit for themotor magnet M. LR restoring opens the initial circuit for relay R, buta substitute circuit is established as described in the pre viousdescription of the operation of the circuit. Immediately upon thedenergiza tion of relay LR, an energizing circuit for relay CO isestablished as previously traced and closes its alternate contacts 32and 33 to extend the calling subscribers line to the secondary lineswitch. Upon the energization of relay C0, of primary line switch B, acircuit for the line relay LR of secondary line switch C is established,as previously traced. Relay LR upon energizing closes the circuit forrelay R as before described. Immediately upon the energization of therelay R the circuit of relay LR is opened at contact 41 and the wiper 16being on an idle contact no substitute looking circuit is establishedfor relay LR The relay LR deenergizes due to the fact that contact 41opens before contact 50 is closed, and therefore no circuit for motormagnet M is established.

The closure of alternate contact 45 of relay R closes a substitutecircuit for relay R of the switch B. The relay R is slow to release andremains operated until a substitute circuit is established from round atthe alternate contact 53 of relay RR of the first selector D. Upon thedeenergization of relay LR a circuit for relay CO is established, andthe closure of the alternate contacts 42 and 43 extends the circuit ofthe calling subscriber to the idle first selector upon which the wipers16, 17 and 18 are resting. From theforegoing it is apparent that asubscriber may connect his line through his individual line switch and asecondary switch to a first selector switch l without moving the wipersof either switch.

The calling subscriber having seized an idle first selector switchbyeither connecting them without moving either primar or secondary lineswitches, or by moving oth or by moving only one,.either the primary orsecondary, is now read to operate his dial to call the first digit ofthe called number.

It will be remembered that the number as signed to the called substationF is 243. and therefore, the first act of the calling subscriber tocomplete the call is to operate the calling device CD to cause twointerruptions of its contacts 21 which results in two deenergizations ofrelay PR. Although the deenergization of the relay PR causes theinterruption of the circuit of main release relay MR at contact 55,relay MR being a sluggish relay does not retract its armature until acontinued deenergization of relay PR is efi'ected as that of replacingthe receiver upon the switch hook at the calling substation A. The saidoperations of relay PR which are effected by the calling device asstated will cause two current impulses to be transmitted to the rimarymagnet PM and secondary relay ER over a path traced from ground atnormal contact 53 through alternate contact 58 of relay MR, overconductor P, normal contact 59 of secondary off-normal springs SON tothe point 60, the current dividing, one path continuing over conductor61 and through the winding of the primary magnet PM to battery, theother ath passing through the secondary relay R to battery. Relay SRbeing a sluggish relay is energized responsive to the first impulses andmaintains its armature attracted until the cessation of the impulses,thus maintaining its normal contact .62 interrupted during thetransmission of the impulses. Two operations of magnet PM affect twoprimary steps of the wipers '24, 25 and 26 to the second row of contactswhich are the contacts 27, 28 and 29 which lead to the connector E whichis adapted to extend the connection to the called line in a well knownmanner. After the said two impulses have been transmitted the secondaryrelay SR restores, thus closing its nor mal contact 62 and as theprimary oif-normal springs PON have moved to their alternate positionupon the first primary ste of the wipers, the circuit for test relay Tis established from ground at said normal contact 62, through alternatecontact 63 of the primary off-normal springs PON, the normal contact 64of the secondary ofl normal springs SON and through the winding of therelay TR to battery. The relay TR is thereupon energized closing itsalternate contact 65 to establish an energizing circuit for secondarymagnet SM whereby the wipers 24, 25 and 26 are stepped into engagementwith the first set of contacts 27, 28 and 29 of the group selected.

Upon the first secondary step of the wi ers the secondary off-normalsprings S N move to their alternate position and the opening of normalcontact 64 interrupts the initial energizing circuit of the relay TR,but assuming that the first set of contacts 27, 28 and 29 lead to a busyconnector and the test contact 27 grounded, relay TR does not deenergizeas a substitute malntalning circuit is established from the saidgrounded contact 27, through the wiper 24, alternate contact 66 of relayTR, alternate contact 67 of relay MR, conductor 68 and through thewinding of the relay TR to battery, thus maintaining the operatingclrcuit for the secondary magnet SM. The magnet M is again operated toadvance the wipers 24, 25 and 26 and continues to do so until an idleset of contacts is reached, and the circuit for relay TB is interrupted,thereby allowing it to deenergize and open the cir cuit of magnet SM.Upon the deenergization of relay TR ground is connected to the multiplecontacts 27 from normal contact 66, thereby rendering the selected setof contacts, 27, 28 and 29 busy and preventing any other switch fromconnecting thereto. The closing of normal contact 66 of relay TRestablishes a circuit for the relay 70 of the connector switch E tracedfrom batte through the winding of the said relay 70, the normal contact71 of release relay BB contact 27 and wiper 24 to ground at normalcontact 66. The'operation of the relay 70 at this time is onlyincidental.

The subscriber at the calling substation A now actuates his callingdevice to transmit four impulses of current which brings about fourdenergizations of the primary relay PR. Four denergizations of the relayPR bring about the operation of the primary magnet PM and the secondaryrelay SR of the connector switch E, the circuit thereof'being tracedfrom ground to normal contact 53, alternate contact 58 of relay MR,conductor-P, normal contact 72 of relay TR, wiper 25, contact28,conductor P normal contact 73 of relay 110, conductor 74, normal contact75 of the secondary off-normal springs SON to the point 7 6, the currentdividing, one path continuing to the normally closed contact 77 oftheswitching re lay SW and through the winding of the primary magnet PMto battery, the other path continuing from point 76 through the windingof secondary relay SR to battery and ground. Responsive to the firstimpulse,

the secondary relay SR is energized and being 'a sluggish relaymaintains its arma ture attracted. until thecessation of thefourimpulses. The four impulses of current flowing through the magnetPMcauses four.

operations of the said primary magnet PM and effects four primary stepsof the wipers 77, 78 and 79 to the fourth row of contacts rent dividinwhich includes contacts 80, 81 and 82, this row of contacts includingthe terminals of the line of the called substation F. Following thecessation of the said four impulses, secondary relay SR denergizesclosing a path for current through the switching relay SW the circuitbeing traced from battery through the winding of the relay SW normalcontact 83 of switching relay SW the normal contact 84 of the relay SEto ground at alternate contact 85 of the pri mary off-normal contactPON. The relay SW upon energizing, closes a locking circuit for itselfestablished throughits alternate contact 83. over the conductor 86 tothe grounded private conductor 87. The opera tion of relay SWdisconnects the primary magnet PM and connects secondary magnet SM incircuit with the conductor P to take the next set of impulses. Thecalling subscriber now actuates the calling device CD to effect threeinterruptions of the calling device springs 21 thereby causin threeoperations of the primary relay P Responsive to these three operationsthree impulses of current are transmitted through the secondary relay SRand secondary magnet SM traced from ground at normal contact 53 of relayPR over the previously traced ath over conductor P to normal contact 3,conductor 74, normal contact 75 to the point 7 6, the circuit dividing,one path continuing through alternate contact 77 of relay SW normalcontact 88 of release relay RR through the winding of the magnet 'SM andnormal contact 89 to battery and ground. The other path of currentcontinues from the point 76 through the winding of the relay SR tobattery. Relay SR is energized upon the first impulse closing itsalternate contact 90. Upon the first secondary step of the switch thesecondary olfnormal switch contacts SON are moved to their alternateposition, and the contact 75 assumes its alternate position therebyinterrupting the initial path for the current imulses through the saidnormal contact 75. owever, a new ath for impulses flowing through magnetM is provided, extending from conductor 74, through alternate contact 90of relay SR to the point 76, the curpart passing through alternatecontact 7 of SW to normalcontact 88 and through the winding of magnetSM? to battery and ground at normal contact 89, and part passing throughrelay SR to battery. The result of these three impulses of current isthat magnet S'M. steps wipers 77, 7 8 and 79 into engagement with thedesired set of contacts 80, 81 and 82 which are the con- 12 tactsconnected with the called subscribers line. Following the last impulserelay SR de'nergizes closing its normal contact 91 thereby connectingthe upperwinding of the line test relay LT-tothe terminal 80 of the 30calied line for the purpose of testing said iine for its idle or busvcondition.

to this period in the operation of the system, the operation is the samewhether connecting to an idle or busy line. Assuming that the calledline is idle, a path for current through the upper Winding of relay LTis provided by the closing of normal contact 91, the circuit beingtraced from ground at normal contact 92 of relay 93, through thealternate contact 94 of relay 70, the normal contact 91 of relay SRthrough the 'upper winding of the relay LT, the conductor 95, the wiper77, contact 80, and throu%h the winding of the relay (:0 of switch 1 tobattery and ground at normal contact 40 of relay R The relay LT uponenergizing closes a locking circuit for itself through its alternatecontact 96, over a circuit traced from battery through the alternatecontact 97 of relay 70, the lower winding of the rela LT, the alternatecontact 96 of relay L conductor 197, alternate contact 94 of relay 70,and the normal contact 92 of relay 93 to ground. The closing ofalternate contact 100 of relay LT shunts its upper winding and places adirect ground from the conductor 197 through alternate contact 100, overconductor 95, to test wiper 77 maintaining the relay c0 energized andalso preventing any other connector switch from establishing connectionwith the terminals of the called line F. The closing of alternatecontact 101 of the relay LT establishes an energizing circuit for therelay 102 traced from battery through the winding of relay 102, thealternate contact 101 of said relay LT to ground at normal contact 92,bringing about the energization of the said relay thereby interruptingits normal contact 103 to disconnect the busy back apparatus BB from thesecondary conductor S The closing of contacts 104 and 105 of relay 102connects battery and ground to the termi-- nals of the ringing controlrelay RC. Also upon the energization of the relay LT an energizingcircuit for the ringing interrupter relay R1 is established, the circuitbeing traced from battery through the normal contact 106 of relay 93,the alternate contact 107 of relay LT and through the windin of therelay RI through the interrupter to ground. The relay R1 is thusintermittently energized and denergized to connect ringing generator Gwith the terminals of the called line, the path of the ringing currentbeing traced from the ungrounded pole of the generator G throughalternate contact 108 of relay R1, the wiper 78, bank contact 81,through the condenser and call bell of the called substation F, backthrough bank contact 82, wiper 79 to the grounded pole of the generatorGr through the alternate contact 109 of the '7, II relay RT. The bell ofthe called substation F is thus intermittently rung, and upon theresponse of the called subscriber at the substation F a circuit for theringing control relay RC is established, traced from ground through thealternate contact 104, the upper Winding of the relay RC, the normalcontact-108 of relay RI (when relay R1 is in its deenergized position),the wiper 78, contact 81 through the now closed contacts of thesubstation switch hook back through contact 82, wiper 79, normal contact109, through the lower winding of the relay RC, and alternate contact105 to battery at alternate contact 97 of relay 70.

Upon the energization of relay RC an energlzing circuit for the relay110 is closed, sald circuit being traced from battery through thewinding of the said relay 110 to ground at alternate contact 111 of therelay RC. The closing of alternate c011- tact 112 of relay 110establishes an energizlng circuit for the relay 93, said,circuit beingtraced from battery through the alternate contact 112 of relay 110,through the winding of the relay 93, the conductor 113, to ground atalternate contact 85 of the primary off-normal springs PON. The relay93, upon energizin closes a locking circuit for itself traced frombattery through its alternate contact 106 and through the winding of thesaid relay 93 to ground at contact 85 of the primary off normal springsPON The opening of normal contact 106 interrupts the circuit of therelay RI thus preventing further application of ringing current. Theenergization of the relay 110 brings about the closing of contacts 73and 114 which establishes the continuity of the talking conductors tothe called subscriber 105 at substation F. The talking circuit betweenthe calling subscriber A and the called subscriber F may now be tracedover the heavily marked conductors, the said conductors having thecondensers K at K interposed at the first selector D.

After the subscribers have finished conversation, they may cause therestoration of the switches used in establishing the connection, thecalling subscriber A controlling the 115 r estoration of the firstselector D, while the subscriber at the called substation F controls therestoration of the connector switch E. Assuming that the subscriber at Ais first to replace his receiver upon the switch hook, the circuit ofthe primary relay PR is interrupted causing the restoration of the saidrela and bringing about the interruption oft e alternate contact 55allowing the deenergization of the main release relay MR.Thedeenergization of the main release relay MR establishes a circuit forthe test relay TR effecting the restoration of the switch D in thefollowing manner. The circuit of relay TR established by the deener- Igization of the relay MB- is traced from ground at normal contact 62 ofrelay SR, alternate contact 63 of the primary oif-normal springs PON toconductor 120, the normal contact 67 of relay MR, the conductor 68 andthrough the windin of the relay TR to battery. Following t eenergization of the relay TR, the circuit is a-galn closed for thesecondary magnet SM due to the closure of alternate contact 65. Thewipers 24, 25 and 26 are step d ahead by the operation of the magnet Muntil they have passed one ste beyond the last contact set in the row.llpon reachin this position, a release pawl is automatical y trippedwhereby the wipers restore from their PIlma ry ad'ustment by a springwhereby switch P( N is restored interrupting its alternate contact 56 toeffect the restoration of the switch D from its secondary adjustment aswill be described. Upon the wipers being restored from their primaryadjustment, a second pawl is tripped whereby they are restored by aspring from their secondary adjustment to normal causing the restorationof the switch SON.

It will be noted that while wipers 24, 25 and 26 are being adjusted totheir normal position, the line conductors are open at normal contacts72 and 72 thus preventing interference with any existing connections.When the wipers restore from their primary ad'ustment, the primaryoff-normal springs PN restore bringing about the opening of theoff-normal contact 63 thus interrupting the circuit of relay TR whichrestores. As soon as alternate contact 56 of switch PON is interru tedas stated, the locking circuit for relay T1 of the secondary line switchC is interrupted as it will be remembered that relay R has beenmaintained energized by current flowing over the test conductor to thegrounded alternate contact 56. Therefore, relay R restores opening itsalternate contact 51 thus interrupting the circuit of the relay G0 whichis deenergized and switch 0 is again available for use in establishingother connections. The opening of alternate contact 45 of relay R ofsecondary switch C brings about the restoration of the relay R ofprimary switch 'B and the o ening of alternate contact' lO of the relayopens the circuit of the relay C0 of primary switch B, permitting therelay CO to restore, the .switch C being again available for use inestablishing other connections.

To release the connector switch E, the subscriber at the substation Frestores his receiver whereby the circuit for ringing control relay RCis interrupted causing its deenergization. Its contact 121 is thereforeinterrupted, disconnecting ground from the conductor 122 therebyinterrupting the circuits for relay 102 and LT of. connector E,

aiid relay 00 of the primary selector B associated with the calledsubstation F causing their restoration. The restoration of the cut-offrelay c0 restores the substation control of the. primary line switch BAlso, upon the deenergizatlon of relay RC, its alternate contact 111 isinterrupted, allowing the restoration of rela 110 whereby a circuit forrelease relay R 1 is established from battery at normal contact 112,alternate contact 123 of relay 93 through the winding of from saidgenerator to advance wipers 77, 78

and 79 beyond the last contact in the row whereby they are automaticallyrestored by spring tension as in the case of the first selector. Uponretraction of the primary ofi'-' normal springs PON, the circuit ofrelays 93, RR, and SW are interrupted causing their restoration. Theswitch E now being at normal is available for use in establishing otherconnections.

Assuming now that the called line is busy, the operation of the systemwill proceed as previously described up to the final deenergization ofthe secondary relay SE of the connector switch E. It will be rememberedthat at the final deenergization of relay SR after the wipers haveconnected to the terminals of line F, relays SW and 7 0 are in anenergized condition. Therefore, upon the denergization of relay SR theupper winding of relay LT is connected in circuit with the test wiper 77of the test contact 80 of the called line as before.

Assuming the line F busy as a calling line, its test contact 80 is onopen circuit as relay R is energized or if the line F is busy as acalled line, its test contacts are con- .nected to ground back overconductor 95 as previously described. I Therefore, when the upperwinding of relay LT is connected in circuit with the test contact 80,there will be no energizing circuit for the said winding as its lefthand terminal is connected to ground at normal contact 92 and there willbe no flow of battery and therefore relay LT does not energize. Relay LTfailing to energize, neither relays 102 nor R1 are energized so that thebusy back signal BB remains in connection with the secondary conductor Sthrough'alternate contact 130 of the switch SON and normal contact 103of relay 102 to the heavily marked'conductor over line conductor- 2,through the receiver of the substation returning over line con ductor 1and overthe heavily marked rimary conductor P to the left hand win ingof the-.relay PR. of the first selector D to -ground. The subscriberupon replacing hisreceiver upon the switch hook causes the restorationof theapparatus used in establishing the connection in the followingmanner.

Due to the replacing of the receiver at substation A, the circuit ofrelay PR is interrupted causing itsdeenergization followed by thedeenergization of the main release relayMR thereb causin the restorationof-the switch D ollowed y the restoration of the switches C and'B aspreviously described. It will be remembered in a previously describedconnection that the connector .E is restored by the subscriber at thecallecl'sub-station F, but in this instance its restoration iscontrolled by the calling subscriber. It will be remembered that relaysand SW are theonly relays energized in switch E, in this instance beinglocked up'over a circuit including test conductor 87 and the ound atnormal contact 66 of relay TR of selector D. Therefore, upon theenergization of relay TR and the restoration of switch D as described,its normal contacts 66 being'interrupted, relays 70 and SW aredeenergized. Following the deenergization of relay 70, a circuit forrelease relay BB is established from ground at alternate contact of PONthrough the winding of said relay RR, normal contacts 123 and 97 tobattery. Relay RR, upon energizing, closes its contact 71 connectingground to its test conductor 87 and contacts 27, preventing any otherswitch from making connection with connector E during its release.Although relay SW deenergizes as just stated at the time its en ergizingcircuit is interrupted at relay TR it immediately energizes again uponthe closing of its normal contact 83 due to the main connection for PONand is again locked up through its alternate contact 83 to ground atalternate contact 71, remaining so until the restoration of PONReturning now to relay RR the closing of its alternate contacts 88 and89 causes the releasing operation of magnet SM as previously describedwhereby switch F is restored to normal causing the restoration of theprimary off normal contacts PON and relays RR and SW Switch E is now atnormal and available for use in establishing other connections.

Havin given the description of the operation of t e system in extendinga call from a calling substation to a called substation, I will nowdescribe one method which may be employed in distributing the trunksbeswitches.

,ary selectors.

tween the rimary and secondary, line switches. owever, it is to beunderstood the primary and secondary trunks are applicable to minvention, one method being shown for i1 ustrative purposes only. Theprimary line switches are arranged in ondary line switches are alsodivided into ten groups In Fig. 4 I illustrate dia ammatlcally twogroups B and B of pnmary switches, each group containing 1,000 line Thisillustration is made on the basis of three equals ten. That is ten lineswitches are shown by three smal and three groups of three small circlesequal ten times ten or one hundred line switches and so on. At T and T Ishow two groups of primary trunks, each group comprising 1 circles,

that various other methods of distributing v three groups of ten trunks,that is one hundred trunks each trunk leading to three groups C, d andC" of secondary switches, each group of secondary switches compris 111gtwo groups of ten each of said secondary line switches, making twentysecondary line switches in a group for each of the tengroups ofsecondary line switches. With each of these three groups of secondaryswitches, I show a group of first selectors D, D and D,- each groupcomprising ten first selectors. As herein shown, the first trunk of thefirst primary group leads to the first switch of the first secondarygroup, the second trunk of the first primary group leads to the firstsecondar switch of the second secondary group an the third trunk of thefirst primary group leads to the first secondary switch of the thirdsecondary group, etc., for the ten trunks. The first trunk of the secondhundred primary switches in the first group B leads to the secondsecondary switch of the first secondary grou and the second trunk of thesecond hun red group of the first grou B leads to the second secondaryswitch and so on. The first trunk associated with the first one hundredprimary switches of the second group B leads to the eleventh secondaryswitch of the first group of second- It is thought that the scheme oftrunking of the diagram as illustrated in Fig. 4 may be readily followedout from the above description. It may also be readily seen that amethod of ten per cent. trunking is maintained, and in the abovedescription the trunks of each group of one hundred subscribers haveaccess to one hundred first selectors making a system of this kind moreflexible and distributing the load among all of the one hundred firstselectors. Should all of the selectors of the first group D be busy, thetrain of relays 19, 19 etc., associated with this first group D wouldoperate to energize relay 22, as previously described, and all of theidle trunks leading to the first group C of secondary selectors would bemade busy.

While I have ilustrated my invention operating in connection with acertain form of selector and connector, it is to be understood that myinvention is readily adaptable to other systems and that changes andmodifications may readily suggest themselves, and I therefore do notwish to be limited to the exact structure and method of trunking asillustrated, but aim to cover all such changes and modifications whichcome within the spirit and scope of the'appended claims.

What I claim as new and desire to secure by United States Letters Patentis:

1. A telephone system including groups of primary switches, secondaryswitches accessible to said primary switches and divlded into groups,said primary and secondary switches being provided with contact makersadapted to remain in their antecedent progressive positions, a group offirst selector switches for each group of secondary switches, and meansfor preventing any primary switch from connecting to an idle secondaryswitch in a group where all the first selector switches are busy.

2. A telephone system including a sub- 'scribers telephone line, a firstselector switch, a secondary progressively movable non-restoringtrunk.selecting rotary switch provided with an individual driving magnetand wipers for directly connecting to a trunk leading to said firstselector switch, a primary progressively movable non-restoring trunkselecting rotary switch provided with an individual driving magnet andwith wipers for directly connecting said calling subscribers line to atrunk extending to said secondary switch, said switches being arrangedto directly connect the calling subscriber to the first selector switchwithout moving said switch wipers if said switches are idle at the timethe calling subscriber initiates a call, and means for afterwardoperating said first selector switch in accordance with the first digitof the called number.

3. A telephone system including subscribers telephone lines, a firstselector switch, a secondary non-restoring automatic trunk selectingswitch provided with wipers for directly connecting to a trunk leadingto said first selector switch, a primary nonnumerical automatic trunkselecting switch provided with wipers for directly connecting a callingone of said subscribers lines to said secondary switch, said switchesbeing adapted to remain in their antecedent progressive positions at thetime of release and to extend connections without moving their wipers ifsaid wipers are in engagement with idle contacts, andsubstation-controlled means for operating said first selector switch inaccordance with a digit of the called number to extend a connection inthe direction of the called subscriber.

41-. A telephone system including subscribers telephone lines.non-restoring rotary trunk selecting primary switches, non-restoringrotary trunk selecting secondary switches, contact makers for each ofsaid primary switches normally in engagement with the last secondaryswitch used, contact makers for each of said secondary switches normallyin engagement with the last first selector switch used, first selectorswitches, operating mechanism for said rotary switches, and substationcontrolled means for operating the'mechanisms of said primary andsecondary rotary switches to connect idle first selectors with callinglines, said actuations of the switches to connect calling lines withfirst selector switches being established Without operating the motormagnets of the primary and secondary switches if the wipers of the sameare in engagement with idle trunks.

5. A telephone system including subscribers telephone lines,non-restoring r0- tary primary switches, non-restoring rotary secondaryswitches, contact makers for said primary switches normally inengagement with the last secondary switches used, contact makers forsaid secondary switches normally in engagement with the last firstselector used, first selector switches, operating mechanism for saidrotary switches, substation controlled means for operating themechanisms of said primary and secondary rotary switches toconnect idlefirst selectors with calling lines, said connections being eilectedwithout operating the motor mechanism of the primary-and secondaryswitches if the wipers of the primary and secondary switches are inengagement with. idle trunks at the time that calls are initiated, andmeans for disassociating said calling subscribers lines and said firstselector switches while maintaining said rotary switches in theirantecedent progressive positions.

6. A telephone system including subscribers telephone lines, a firstselector switch, a secondary non-numerical non-restoring trunking switchhaving movable contact makers normally in engagement with a trunkdirectly connected to said first selector switch, a primarynon-restoring non-numerical trunking switch having contact makersdirectly in connection with a trunk leading to said secondary switch,said primary and secondary switches being for use in efi'ectingconnection between a calling one of said lines and said first selectorswitch, and means controlled by the removal of the receiver at thesubstation of said calling line for effecting said connection whilemaintaining said non-numerical switches in their antecedent progressivepositions, without moving the contact makers of sald trun ing switches,1

7. A telephone system including a subscribers telephone'line, anindividual switch for said line, secondary switches accessible to saidindividual switch, first selector switches accessible to said secondaryswitches, trunks inter-connecting said individual and said secondaryswitches, contact makers for said individual switch normally inengagement with its bank contacts connected to said secondar switches,contact makers for said secon aryswitches normally in engagement withbank contacts connected direct y to said first selector switches, trunksinterconnecting said secondary and said first selector switches, andmeans controlled over the calling subscribers line for operating saidindividual switch and an idle one 0 said secondary switches to extend aconnection to .an idle first selector switch while maintaining saidindividual and secondary switches in their antecedent progressivepositions if they are in connection with idle trunks.

87in automatie progressively movable switch, a pair of test wipers forsaid switch, banks of coiiperating contacts for cooperation with saidwipers, a control relay for said switch, means for energizing saidrelay, and means controlled by said test contacts and wipers to maintainthe said control relay in energized position if either of said wipersare inengagement with busy contacts. p

9. An automatic progressively movable trunk selecting switch, a pair oftest wipers for said switch, coiiperating bank contacts for said wipers,a control relay, means for energizing said control relay, and means formaintaining said relay energized as long as either of said wipersengages busy bank contacts.

10. A telephone system including subscribers telephone lines, groups ofprimary rotary non-restoring switches for said subscribers lines,contact makers for said primary switches adapted to always be rotated inthe same direction, secondary rotary nonrestoring switches accessible tosaid primary rotary switches, a group of first selector switches foreach group of secondary switches, and means for preventing a primaryswitch from connecting to an idle secondary switch in a group where allthe first selector switches are busy.

11. A telephone system including subscribers telephone lines dividedinto groups, individual rotary non-restoring switches di vided intogroups corresponding to the groups of subscribers lines, groups ofsecondary switches accessible to said individual switches, contactmakers for said secondar switches adapted to always be rotated in thesame direction, a group oi first selector switches for each group ofsecondary switches, said first selector switches of any group being lessin number than the number of secondary switches in a group,and means forpreventing, a primary switch fromconnecting to an idle secondary switchin a said primary and secondary switches adapt-- ed to always rotate inthe same direction, a numerical switch, means controlled by the callingsubscriber for connecting to said numerical switch via said primary andsecondary switches, and substation controlled means for operatin saidnumerical switch in accordance with t e first digit of the called numberto extend the connection in the direction of the called line. i

13. A telephone system including a calling subscribers line, a firstselector switch, a secondary trunk selecting switch having its wipersnormally in engagement with a trunk extending to said first selectorswitch, a primary switch having its wipers normally in engagement with atrunk extending to said secondary switch, meansfor connecting saidcalling subscribers line to said first selector switch via said primaryand secondary switches while maintaining the wipers of said primary andsecondary switches in connection with said trunks, and means -fordisconnecting said calling line from said first selector switch whilemaintaining said primary and secondary switches in their antecedentpositions.

14. A telephone system including subscribers telephone lines dividedinto groups, primary switches likewise divided into groups andindividual to the subscribers lines, secondary switches divided intogroups, contact makers for said primar switches always in engagementwith secon ary switches, a group of' first selector switches for eachgroup of secondary switches, and means common to a group of firstselector switches for rendering busy all idle secondary switchesassociated with said group of first selector switches when said rstselector switches all become busy.

15. A telephone system including primary switches divided 1nto groups,secondary switches divided into groups and accessible to said primaryswitches, a group of first selector switches for each group of secondaryswitches, contact makers for said secondary switches always inengagement with said first selector switches, means for including allthe first selector switchesin one group in conversational circuits, andmeans for preventing primary switches from connectin with any idlesecondary switch associate with said group of first selector switches.

16. An automatic switch having a pair of test wipers and a pair of linewipers, cooperating contacts or said wipers, a relay individual to saidsw1tch,-means for energizing said relay, and means for maintaining saidrelay energized as long as either of said test wipers engages busy bankcontacts.

17. A telephone system includ ng a subscribers line, an automatic swltchindividual thereto passive ank contacts for said test wipers a testrelay for said switch, and means or maintaining said relay in itsoperative pos1- tion as long as either of said wipers engages busypassive contactsr vl8. A telephone system including a subscriberstelephone line provided w1th an individual rimary switch, a secondarytrunking swltch having only three movable contact makers accessible tosaid prlmary switch, a first selector switch accessible to.

said secondary switch, bank contacts for said secondary switch havingconductors connected thereto and directly extending tosaid firstselector switch, and subscriber controlled means for extending aconnection through said primary and secondary switches to said firstselector switch without moving the wipers of said primary and secondaryswitches.

19. A telephone s stem includlng a subscribers telephone ine, a trunkselecting switch individual thereto, a secondary trunk selecting switch,having only three contact makers, bank contacts for -said secondarytrunk selectin switch, a first selector switch, trunk con uctorsconnecting the bank contacts of the secondary switch directly to saidfirst selector switch, movable contact wipers for said individualswitch, means for extending a connection from said subscribers linethrough said individual and secondary switches to said first selectorswitch, and means for releasing said connection without alterin theantecedent progressive positions 0? said individual and secondaryswitches.

20. A telephone system including a sub-. scribers telephone line, atrunk selecting switch individual thereto, a secondary trunk selectingswitch provided with only three contact wipers, a air of talking wipersand a test wi er, a rst selector switch, bank contacts or said secondarytrunk selecting switch conductors extendin directly from said bankcontacts to sai first selector switch, individual contact wipers forsaid individual switch, means for extending a connection from saidsubscribers line through said individual and secondary switches to saidfirst selector switch, means for releasing said connection, and meansfor reestab- Erovided with a pair of test wipers,

lishing said connection without moving the wipers of said individual andseconda swltches.

of primary switches, secondary switches divided into groups accessibleto said primary switches, contact makers. for saidprimary switchesalways in engagement with secondary switches, a group of first selectorswitches associated with each group of secondar switches, contact makersfor said secon ary switches always in engagement with the first selectorswitches, and means for reventing any one of said primary switc es fromconnecting to a secondary switch in a group associated with a group ofbusy first selectors.

. 22. A telephone system including subscribers telephone lines,non-restoring rotary primary switches, non-restoring rotary trunkselecting secondary switches, trunks leading from the banks of theprimary switches directly to the said secondary switches, connectivelinks, trunks leading directly from the banks of the secondary switchesto said connective links, individual operating mechanism for said rotaryswitches," substation. controlled means for operating the mechanisms ofsaid primary and secondary rotary switches to connect idle connectivelinks with calling lines, means for disassociating said cal-lingsubscribers lines and 'said connective links while maintaining saidrotary switches in their antecedent progressive positions and withoutactuating said operating mechanism, said switches now being effective toextend other connections from the calling lines to theconnective linkswithout actuating the operating mechanism of the switches whereby saidconnections are completed without moving the active contacts of therotary switches.

23. A telephone system including groups .of primary trunks selectingnon-numerical progressively movable switches of the nonrestoring typeadapted to remain in their antecedent progressive positions, secondarytrunk selecting progressively movable non-numerical switches accessibleto said primary switches divided into groups, a group of first selectorswitches for each group of secondary switches, trunks leading directlyfrom the banks of the secondary switches to said first selectorswitches, and means for preventing any primary switch 21. A telephonesystem including a. group from connecting to an idle secondary switchaeaasvl numerical switches, means controlled by the removal of thereceiver at the substation of said calling line for effecting saidconnection while maintaining said non-numerical switches in theirantecedent progressive positions, and means for disconnecting said linefrom said connecting link while maintaining said contact makersin theirselective positions.

25. A telephone system including a group of primary switches, secondaryswitches of the non-restoring type adapted to remain in their antecedentprogressive positions and divided into groups accessible to said primaryswitches, a group of first selector switches associated with each groupof secondary switches, and means for preventing any of said primaryswitches from connecting to a secondary switch in a group of secondaryswitches where all the first selector switches associated therewith arebusy.

26. A telephone system including a calling subscribers line providedwith an individual non-numerical trunk selecting rotary switch, asecondary non-numerical trunk selectin rotary switch accessible to saidindi- 'vidua rotary switch, motor mechanism for each of said switches, aconnective link, trunk conductors extending directly from saidconnective link to bank contacts of said secondary switch, and meansunder the control of the calling subscriber for operating the individualmotor mechanisms of said rotary switches to operatively connect thecalling line with said connective link, said switches being operative toextend a second connection from said calling line to said connectivelink without operating the motor mechanisms of the switches if saidswitches are on idle contacts when the second connection is efiected.

27. A telephone system including a calling subscribers line, anautomatic non-numerical trunk selecting switch individual thereto, asecondary automatic non-numerical trunk selectin switch accessible tosaid first automatic switch, motor mechanism for each of said switches,a connective link, conductors extending directly from the bank of saidsecondary switch to said connective link, means responsive to theremoval of.

the receiver at the calling substation to connect said connective linkwith said calling line via said rotary switches without operating themotor mechanisms of said rotary switches, and means for extending aconnection from said connective link to a called subscribers line,thereby completing a talking connection involving the said primary ndsecondary switches and the said connective link.

128. A telephone system including subscribers telephone lines,non-restoring primary rotary trunk selecting switches, nonrestoringsecondary rotary trunk selecting switches, connecting circuits, trunkconnections extending directly from the banks of the rotary switches to,the connecting circuits, individual operating mechanisms for saidswitches, substation controlled means for operating the mechanisms ofsaid primary and secondary switches to connect idle connecting circuitswith calling lines and for disconnecting subscribers lines from saidconnecting circuits without operating sa d operating mechanisms, saidswitches being operable to now extend other connections from callinglines to idle connected circuits without operatin the mechanism of theswitches, and means or completing connections from said connectingcircults to called subscribers lines, said connections includlng primaryand secondary trunking switches and one of said connecting circuits.

29. A telephone system including a calling subscribers line, aconnective link, a secondary trunk selecting non-numerical switch havingits wipers normally in engagement with a trunk extending to saidconnective link, a primary trunk selecting non-numerical switch havingits wipers normally in engagement with a trunk extending to saidsecondary switch, means for connecting said calling subscribers line tosaid connective link via said primary and secondary switches whilemaintaining the wipers of said primary and secondary switches inconnection with said trunks, and means for extending a connection fromthe connective link to a called subscribers line, the completedconnection includin the primary irndr secondary switches and t econnective 30. A telephone system including subscribers telephone lines,groups'of primary non-restoring switches for said subscribers" linesprovided with individual motor mechanisms, secondary non-restoringswitches accessible to said primary switches, a group of connectivelinks for each group of secondary switches, and means for preventing aprimary switch from connecting to an idle secondary switch in a groupwhere all the connective links are busy. 1

31. A telephone system including a group of primary switches, secondaryswitches di-' said connective link via said primary and secondaryswitches while maintaining the wipers of said primary and secondaryswitches in connection with said trunks, means for disconnecting saidcalling line from said connective link while maintaining said primaryand secondary switches in their antecedent positions, and means forcompleting a talking connection between said calling subscribers lineand a called subscribers line, said talking connection when completedincluding said connective link and said primary and secondary trunkingswitches.

33. A telephone system including a subscribers telephone line,connective links, primary and secondary rotary switches for connectingsaid calling line to an idle connective link, said primary and secondaryswitches being of the non-restoring type and provided with movablecontact makers to always rotate in the same dlrection, and substationcontrolled means for connecting said calling line to an idle one of saidconnective links and for operating the switch adjusting mechanisms ofsaid primary and secondary switches only if the trunks that they are inconnection with are busy.

34. A telephone system including a 'subscribers telephone line, anindividual nonnumerical trunking switch for said line, secondaryswitches accessible to said individual switch, connective linksaccessible to said secondary switches, trunks interconnecting saidindividual and said secondary switches, trunks interconnecting saidsecondary switches and said connective links, means controlled over thecalling subscribers line for operating said individual switch and anidle one of said secondary switches to extend a connection to an idleconnective link while maintaining contact makers of said individual andsecondary switches in their antecedent progressive positions if they arein connection with idle trunks, and means for directly extending thetalking connection from an idle connective link to a called subscribersline.

35. A telephone system including primary switches divided into groups,secondary switches divided into groups and accessible to said primaryswitches, individual stepby-step motor mechanism for each of saidprimary and secondary switches, a group of connective links for eachgroup of secondary switches, means for including all of the connectivelinks in one of said groups in conversational circuits, and means forpreventing primary switches from connecting with secondary switchesassociated with said engages busy bank contacts.

37. A telephone system including an automatic switch provided with aline wiper and with a pair of test wipers, individual motor mechanismfor said switch, cooperating bank contacts for said wipers, test, meansfor said switch, means for operating said testmeans and for maintainingsaid test means operated as long as either of said test wipers engagesbusy bank contacts.

38. A telephone system including a subscribers telephone line,connective links, primary and secondary non-restoring trunk selectingswitches for connecting said telephone line to an idle one of saidconnective links, contact makers for said switches, trunks extendingdirectly from the bank of the primary switch to the secondary switch andfrom the bank of the secondary switch to the said connective links,substation controlled means for disconnecting said subscribers line fromsaid connective link while maintaining the contact makers of saidswitches in their antecedent progressive positions, and means forcompleting talkingconnections from the calling telephone line throughthe primary and secondary trunking switches and the selected connectivelink to a called subscribers line, said completed connection includingthe idle connective link, and subscriber-controlled means for releasingthe idle connective link.

39. A telephone system including a subscribers telephone line providedwith an individual non-numerical trunk selecting primary switch, anon-numerical secondary trunking switch accessible to said primaryswitch, a connecting linkaccessible to said secondary switch, a trunkextending directly from the bank of the secondary switch to theconnecting link, subscriber controlled means for extending a connectionthrough said primary and secondary switches to said connecting linkwithout moving the wipers of said primary and secondary switches, meansfor extending a connection directly from the connecting link to a calledsubscribers line, and subscriber-controlled means for disconnecting theconnecting link from the called subscribers line.

40. A telephone system including a subscribers line, a link circuit, aprimary and a secondary non-numerical trunk selectin switch forextending connection from sai line to said link circuit, a trunkextending directly from said primary to said secondary swltch and asecond trunk extending directly from the bank of said secondary switchto said link circuit, movable contact makers for each of said switches,subscribercontrolled means for connecting said line to said link circuitwithout moving the contact makers of said switches, means for completinga talking connection with a called subscribers line, andsubscriber-controlled ,means for disconnecting the link circuit from thecalled subscribers line.

Signed by me at Chicago, county of Cook and State of Illinois, in thepresence of two witnesses.

GEORGE A. YANOCHOWSKI.

Witnesses:

MARIE F. O. BREEN, M. R. Roonronn.

